| 摘要 |
<p>PURPOSE: To obtain a simple and inexpensive noise reducing circuit by providing a noise reduction circuit with two S/H circuits for sample-and-holding a reset level signal and an information level signal in a video signal. CONSTITUTION: An input video signal is supplied to a 1st S/H circuit 18. A control signal generated by a pulse generator 62 in the period of a set level signal in a video signal is supplied to the circuit 18 and a switch 48 is temporarily closed to sample a reset level (r). The representative value of the level (r) is stored in a capacitor 50. The stored signal is supplied to a differential amplifier 34 together with the video signal and subtracted from the video signal and an output from the amplifier 34 is supplied to a 2nd S/H circuit 26. A control signal generated from a pulse generator 64 in the period of an information level signal in the video signal is supplied to the circuit 26. The signal samples the information level signal and the sampled signal is stored in a capacitor 58 and can be used by the output terminal 30 of the circuit 26 and the output terminal 42 of a noise removing circuit 16.</p> |
